1. Field of the Invention
The present invention relates to an outer lead bending apparatus for a semiconductor package device which can bend the outer leads extending from a package of the semiconductor package device into a particular configuration and to an apparatus for bending the outer leads of a surface-mount semiconductor package device in particular.
2. Description of the Related Art
A so-called surface-mount semiconductor package device is manufactured by molding a semiconductor element set on a lead frame to provide a package with the semiconductor element covered and bending the outer leads outwardly extending from the package into a predetermined configuration.
For a QFP (quad flat package) with outer leads extending in four directions (X and Y directions), for example, the outer lead bending process is carried out as follows.
That is, the outer lead bending process comprises the vertical bending step of vertically bending all the outer leads extending horizontally in X and Y directions, the X-direction horizontal bending step of horizontally bending the forward end portions of the outer leads extending in the X direction, the Y direction horizontal bending step of bending the forward end portions of the outer leads extending in the Y direction and cutting step of cutting the bent forward end portions of the outer leads to a given length.
The conventional outer lead bending apparatus used to horizontally bend the outer leads in the X and Y directions has the following tasks to be solved.
First, the outer lead bending apparatus has no general-purpose application and products obtained become expensive.
That is, the conventional outer lead bending apparatus for bending the outer leads of the semiconductor package has no general-purpose application and it is necessary that it be used in a one-apparatus-per-product basis.
For the manufacture of semiconductor package devices of various sizes and shapes, therefore, corresponding devices need to be newly designed and manufactured.
Recently the semiconductor package devices have been a tendency to be manufactured on a many-product small-quantity basis. Under this situation, more outer lead bending apparatuses have to be manufactured, thus presenting an equipment investment problem.
Second, the positioning of the upper and lower dies is difficult to achieve.
That is, in order to facilitate the loading and unloading of the semiconductor package device between the upper die and the lower die, the upper die is supported by guide posts mounted upright in a cantilever fashion on one widith-direction side of the lower die, so that the upper die can be moved freely in an up/down direction.
In such an arrangement, a place where the outer leads of the package device are actually bent in the horizontal direction is located remote from the guide posts and, further, the tilting of the guide posts occurs. With a lapse of time, the accuracy with which the upper and lower dies are positioned is lowered due to such tilting of the guide post, thus adversely affecting the quality of products obtained.
Recently, more outer leads are provided in more narrow pitch on the semiconductor package device and higher accuracy is highly demanded in bending the outer leads of the package device. It is, therefore, necessary to position the upper and lower dies accurately and stably.